There are many designs of simple and inexpensive sprinkler heads on the market which are all mounted on standard one-half inch sprinkler pipe and which provide sprinkler patterns of predetermined area coverage by covering, for example, full circles, half circles and quarter circles. Other types of sprinkler heads can be adjusted to water in an arc of any desired angle, but such sprinklers are much more complex and expensive then the types under consideration. Many of the sprinkler heads now in use are simple molded plastic elements with a fixed pattern of holes to provide a fixed watering pattern and which normally include a single screwdriver adjusted valve to control the pressure of water flowing out of the head, hence the distance the pattern will reach and the volume of water flowing through the head.